Troubleshoot Engine OBD Error Codes

Will A Bad Timing Belt Throw A Code?

can a bad timing belt throw a code

When a timing belt in a vehicle is failing, it may not always directly cause a diagnostic trouble code (DTC) to be thrown. This crucial component, responsible for keeping the crankshaft and camshaft in sync, ensures the timely opening and closing of engine valves.

A worn timing belt, stretched or broken, can lead to a myriad of engine issues, necessitating a belt replacement to avert catastrophic engine failure. However, these problems may not immediately result in a particular DTC for the timing belt, meaning the

A bad timing belt or timing chain can, however, cause indirect symptoms that might trigger codes for various engine issues. For instance, a timing belt slipping on the camshaft can disrupt engine timing, leading to low oil pressure, a ticking noise, misfires, poor acceleration, loss of power, or unusual exhaust emissions.

These conditions can trigger a code for camshaft sensor, such as the P0300 (Random/Multiple Cylinder Misfire Detected) or the P0171 (System Too Lean Bank 1), which often indicates a failing timing belt. In engines where the timing belt also drives the water pump, its failure could prompt overheating, potentially triggering relevant trouble codes and putting the engine into limp mode.

Vehicles with advanced diagnostic systems might be more capable of indirectly detecting a failing timing belt, aiding a mechanic in diagnosing and addressing timing belt issues.

Engines use camshaft position sensors and crankshaft position sensors to monitor the exact timing of these parts. A notable discrepancy between expected and actual timing can harm valves and pistons and could lead the engine control unit (ECU) to record a relevant DTC, such as P0016 (Crankshaft Position-Camshaft Position Correlation).

The make and model of the vehicle, along with the sophistication of its diagnostic system (like in a Honda Accord), influence the capacity to indirectly detect these issues like when a timing belt is failing.

In summary, while a bad timing belt might not directly result in a specific DTC for itself, its failure can lead to various engine performance problems that trigger other codes, guiding the mechanic in timely belt replacement and preventative maintenance.


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About the author

The Motor Guy

The Motor Guy is a passionate car enthusiast with a love for troubleshooting and diagnosing all sorts of vehicle problems.

With years of experience in OBD diagnostics, he has become an expert in identifying and solving complex automotive issues.

Through, he shares his knowledge and expertise with others, providing valuable insights and tips on how to keep your vehicle running smoothly.

- 12 years experience in the automotive industry
- ASE Master Automobile Technician
- A Series: Automobile and Light Truck Certification, A9 Light Vehicle Diesel Engine Certification
- Bachelor's Degree in Information Systems


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  • I recently bought a used car and I’m worried about its timing belt based on its mileage. How can I check if the timing belt needs a replacement without specific trouble codes indicating it’s failing?

  • Given that a failing timing belt might not directly trigger a specific diagnostic trouble code (DTC), how can I proactively check for signs of wear without relying on DTCs? I own an older model car and want to ensure I catch any potential issues early.

  • I’ve been noticing my car has been having poor acceleration and a slight ticking noise recently. Could these symptoms indicate a problem with my timing belt, and if so, how urgent is it that I get this checked by a mechanic?